The International Business Machines Corporation (IBM) ESA/390 architecture defines a program status word (PSW) which includes a system mask, an access key, and an address space control. ESA stands for Enterprise Systems Architecture.
Ordinarily, the instructions which modify the PSW system mask, access key, and address space control are executed with overlap disabled. Executing such instructions with overlap enabled could result in violations of the computer systems' architectures. However, executing such instructions with overlap disabled significantly degrades the performance of the computer systems.
In a pending patent application entitled "Overlapped Serialization" (Ser. No. 07/641,987; filed Jan. 16, 1991), an invention is described for processing instructions with overlap enabled which are required by the ESA/390 architecture to be serialized. This class of instructions includes ones which update PSW fields. However, this invention does not describe or suggest a system or method for modifying the PSW with overlap enabled. In "Non-sequential High-Performance Processing" (IBM Technical Disclosure Bulletin, October 1984), an invention for pre-analyzing interdependencies and maximizing parallel execution of instructions in order to reduce processor execution delays is described. However, this invention does not describe or suggest a system or method for storing non-architected PSW values. Further, this invention does not describe or suggest a system or method for modifying the PSW with overlap enabled.
Thus, a system and method for modifying the PSW with overlap enabled are required.